Brooke Lea Foster had an interesting charter school story in the Washingtonian:
1. Closing of non-performing charter schools will introduce survivorship bias into the data on school performance.
2. If the charter school board is quick to close non-performing charters and think that this is the best way to approach it, why do they not do this with public schools (or try to introduce more accountability)? Possible reasons? Unions, bureaucracy?
3. The story doesn't go into what happens to the kids in charter schools that were closed.
4. Most charter schools are small and perhaps this is another "small school" theory. See here, here, and here. The Gates Foundation has sponsored some studies on small schools. See here. Unfortunately, the evidence does not seem compelling for small schools. It's work on charter schools is through the NewSchools Venture Fund but so far I don't see any studies it has done on charter schools.
5. MR summarizes Caroline Hoxby's work on charter schools.
6. An archive of some charter school studies along with ratings of the studies are here.